Pump



Aug. 28, 1928. A 1,682,570

J. E. HOLVECK PUMP Filed June 28, 1926 2' Sheets-Sheet l FII-LZ.

FIELl.

Aug. 28, 1928.

J. E. HoLVEcK PUMP Filed June 28, 1926 2 Sheets-Sheet Kim @w s 4N Y rm.

am... i... v192;.

UNITED PATENT orifice.-

your.

f a'ppnmiaa mea mit as, laas. sem-1 110.418,90?.

This invention relates to pum s and more particularly to that typeadapte to provide a variable delivery in accordance with 'variations indeman buti without any variation in the speed 'at which the pump 1sdriven. .j

An object of this invention is to provide a pump unit of the type'setforthof'improved construction and having a simplified method of control.

A further object is to provide a constant speed, variable delivery pumpwhich is slmp e and rugged in construction, reliable 1n operation andlrelatively cheap to manufactureand assemble.

Theseand other oects which will be apparent to those skill in this.articular art are accomplished b meanso the present.

invention which is illustrated in the accom- 20 panying drawings,`wherein Figure 1 is a view in elevation of a pump unit constructed yinaccordance with one form of this invention. Fig. 2 is a 'transversesectional view on the line 2-2 of Fig. 1. Fi 3 is a simi.-

lar view on the line 3-3 of 1g. l1. Fig. 4-

is a sectonal view on the'line 4.-4 of Fi 3. Figs. 5 and 6 arediagrammatic views i ustrating certain details of operation hereinafterdescribedI and 7 1s a view similar to Fig. 2'show1ng the application ofthe invention to a different form of pump unit.

The particular embodiment of the resent invention which has been chosenfor t e purf' poses .of illustration may be applied to a pump unithaving any desired number of cylinders and includes se yarate t e axialpositions ofw 'ch' are fixed rela tively to eachother. The crank shaftsarev ders in such a way that a variation in thev relative timing of thecrank shafts results inv a variation inthe delivery of the associated lump unit. 1

ischarge valve 15 leading to a discharge oitlet 16.

The o rating mtcla-nism for-'each plung- 'lger is suc that the stroke ofthe plunger can be varied so as vary the delivery from'the Crank shafts,

lconnected by suitable connecting 'rods'with' nular llustra-ted,theinvention is applied to a triple cylinder pumpflO having the usualdifferent pump chambers. As illustrated in Figs. 1y and 2', thismechanism includes a ,cross head 17 pivoted by a pin 18 to the upper endof each plu r.` One end of eaclno cross head is connecte Vto anassociated crank shaft 19 by suitable connecting rods 20 and the otherend of each cross head is connected to a crankshaft 21 by similar rods22. Each crank shaftV is rotatabl mounted Ain station- 05 ary' bearings`so that t e axes of the shafts are fixed relatively to'each other. Thevertical movements ofthe pump plungers are guided by a cradle 23 mounted.between up-` riffhts 24 upon which the crank shaftbear- 7 in's mayconveniently be mounted.

Any convenient source of power such for example, as a motor 25 can beused to riveA .the pump. As illustrated, the motor armature is connectedto a drive shaft 26 having 75 a gear 27 meshing with a driving gear 28on the crank shaft 21. The two crank shafts are geared togetherforruntary movement d the gearing connectin them is of such constructionthat the relative ftiming of the two shafts may be varied so as to varythe stroke ofthe associated plungers. [As illustrated, this earingincludes aspur .gear .29 secured to the crank shaft 21 andmeshing withthe external teeth of an annular rotatably mounted upon the associatshaft 19. An arm 31 is 'rotatably mounted upon the crank shaft L9 andatpone end is j provided with a stub shaft 32 pinned to the arm andpro'ecting into the hollow annulai ao gear 30. .A pur gear 33isrotatably mounted upon the projecting end of the stub shaft and mesheswith the internal teeth of the annular gear 30 on one side and a spurgear 3ft keyed to the' shaft' 19 within the-annular 95v gear 30.0n theother side. *The opposite end of the arm 31 has a stub shaft 35rotatably mounted therein 'and extending into the anar on' the oppositeside of the crank shaft rom the planetary gear 33.` A secondplanetarygear 3.6 is fkeyed to the `stub shaft 35 andmeshes with the internalvteeth of the annular gear-30 on one side and with the spur gear ke edto the crank shaft o n the other side. crankarm 37 is secured 105 tovthe lop osite end of the stub shaft 35 and connecte to a rod 38 for aurpose to be a hereinafter described. The p anetary gear supporting arm.31 has a flange or extension 39 connected by connecting rod 4 0 with a110 plunger 41 received within a cylinder 42, the. lower end of which isconnected by a ar 30 85 I crank V suitable adjustment lill pipe 43 withthe discharge manifold of the pump so that the piston 4l is affected byany variation in the pressure of the pump discharge. A .coil spring 44is provided between'a cross head 45 secured to the plunger 4l and astationary cross head 46 mounted upon rods 47 extending upwardly fromsupports 48 secured to the cylinder 42, see Fig. 3. Obviously, an'increase in the discharge pressure will elevate the planetary gearshifting piston 41 against the pressure of the spring 44 so as to shiftthe planetary gear supporting arm 31, while any decrease in thedischarge pressure of the pump permits the spring 44 to force the piston4l downwardly. The lowermost limit of the con-A necting rod 40 andpiston 41 may be set by of a nut 49 threaded to the connecting rod andadapted to engage the upper stationary cross head 46.

It will be apparent that when the crank shafts are so timed that thecranks a, b and c of the shaft 2l, see Fig. G, are in time with thecooperating cranks a', y and e, respectively, of the associated shaft 19the stroke of the pump plungers 12 will be at a maxi mum and the pumpdelivery willv also be at a maximum. This occurs when the gear shiftingpiston 4l is in its lowest position. Any upward movement of this pistonand corresponding shifting of the planetary gears 33 and 36 will varythe timing of the two crank shafts as such a movement of the planetargears causes a shifting of the relative positions of the ears 29 and 34keyed to the respective sha ts. This in turn causes a correspondingshifting in the-timing of each pair'of cooperating cranks a and m etc.,and a resulting decrease in the plunger travel so as to reduce the pumpdelivery. The gears forming the lanetary gear train are kso formed and osuch relative sizes that the vtwo crank shafts will revolve at the samespeed when the planetary gear shifting arm 39 is stationary. Theproportioning of the gears forminor the gear train is such that amovement of of the gear supporting arm 39 will rotate the gear 34, andconsequently the crank shaft 19, 180 with respect to the assaociatcdcrank shaft 21. If the respective y crank shafts are in the'position'diagrammatically illustrated in Fig. 6, wherein each twoassociated cranks connected to the same piston rise and fall together,the delivery of the pump unit will be at a maximum, as above pointedout. If, now, the demand to be satiied by the pump discharge falls thepressure built up in the discharge line will elevate 4the planetary gearshifting piston 41 so as to shift the planetary gears and change therelative timing of the associated crank shafts. If the demand dropssuiiiciently to shift the gear supporting arm 45 the crank shafts willassume the relative .is shifted to the left as positions indicated inFig. 5, wherein each associated crank moves in opposition to the otherassociated crank. The result is that as one connecting rod 20 rises theother connecting rod 22 falls and there will be no appreciable'movementof the associated plunger 12. Under these circumstances the pumpdischarge is at a minimum.

' As a. matter of actual practice it is impossible to obtain zerodelivery by the above described mechanism, due to the angularity assumedby the connecting rods 2O and 22. In order to obtain zero deliverywithout stopping the pump an arrangement for unloading the pump suctionvalves is associated with and adapted to be operated by the mechanismfor varying the timing of the crank shafts.

The connecting rod 38, heretofore referred to, is continuallyreciprocated by the crank arm 37 and the lower end of the connecting rodis provided with a rack 5U in mesh with and adapted to oscillate a gear5l loosely mounted upon a hollow shaft 52. The oscillating gear has abeveled tooth 53 projecting outwardly on each side thereof, sec Fig. l.The hollow gear supporting shaft 52 is provided with diametricallyopposed slots 54 and a rod 55 extends into one end of the hollow shaftand is provided with a pin 56 extending outwardly on one side of thehollow shaft through one of the slots 54 on one side of the oscillatorygear 5l, and a second pin 57 extending through the other of the slots 54on the opposite side of the oscillatory gear. The rod is slid- -ablelongitudinally of the hollow shaft so that either one or the other ofthe projecting pins 56 and 57 can be shifted to engagement with anassociated tooth 53. 'lhe outer end of the slidable rotatable rod 55 isconnected to the core 58 of a solenoid 59 and is normally spring pressedoutwardly by a spring 6 so as to position the pin 56 in the path of theadjacent gear tooth 53. When the solenoid is energized by closing itscircuit through a switch 61 the rod 55 seen in Fig. 1 and the pin 57 ismoved into engagement with the associated gear tooth 53 while the pin 56is moved out of engagement with the adjacent gear tooth. The end of thehollow shaft opposite the solenoid is connected to a rotatable shaft 62having cams 63 secured thereto beneath each of the suction valve stems14. It will be apparent that when the cam shaft 62 and cams 63 are inthe position illustrated in Fig. 2 the pump will be loaded, but that amovement of of the cam shaft will cause the suction valve stems 14 to beelevated by the high parts of the associated cams so that the suctionvalves will be held away from their seats and the pump cylindersunloaded. The unloading cams are so positioned upon the supporting shaft62 that the pump will be unloaded and the delivery reduced to zero whenthe solenoid 59isde-energized. This permits the spring 60 to expand andmove the rod pin 56 into the path of the oscillating gear toothf53 asshown. The oscillating gear 51 and -gear tooth 53 oscillate lthrough anarc of 1`80 so'athat the 180 movement of the hollo\w shaft 52 and cams I63 causes'tlie suction valves of the pump to be unloaded.4 B energizingthe solenoid the pin 56 is move away from the oscillator gear and thepin 57 is moved into the at ofthe adjacent gear tooth 53 upon its si eof .the oscillatory gear. It is apparent that this causes the camshaft62 and cams 63 to Abe rotated `another 180, resulting in the lowparts of the cams being positioned opposite v the' suction' valves sothat the latter vare rmitted to close. and the pump is loa ed. Thebeveling of the teeth 53, see Fig.' 1, prevents .the pins 56 and .57from beingvv moved except in the desired direction. Back# and resultingin such a movement of the unloading cam 63 .as willunload the pump. Whenthe demand is again in evidence the downward movement of the cross headwill cause the switch 64 to close the solenoid circuit and again loadthe pump. The

manually operable switch 61is, of course,

ward rotationv of the unloading-cams is im-A possible.

Advantage .is taken of this form of operation (for automaticallyunloading the pump when the demand drops to zero and automaticallyloading again when there is a further demand. As illustrated, thisa'uto- Y matic control consists of a 'switch 64 posii tionedin thesolenoid circuit, see Fig. 1, and

adapted to be normally closed. The switch is provided with an operatinghandlel or projection 65 which extends into the path of movement of theslidable cross head 45 movable with. the planetary Gear operatingpiston. As heretofore pointe out, when the vdemand for the pumpdischarge drops the discharge pressure will be increased so that theplanetary gear shiftingpluner 41 and pressure of the spring 44. As tpointed out, 'this upward movement ca cross head 45 are moved upwar lyagainst normally closed during operation ofthe ump. A

It will be'apparent that the crankarm 37 rotates simultaneously with,and at the.

same speed as the pump crank shafts. The `1 cams 63 are rotated byanvupward movement of the crank arm 3 7 and the latter is so timed thateach cylinder will loadonly at thebeginningof a discharge stroke.

This is tosay, thev cams 63 `will'be *rotated only during the suctionstrokes of the vari- /ous cylinders. This prevents the pump loading witha sudden jar and-'causes a gradual increase in torque -from zero tomaximum instead of asudden jarring in.

.crease'to maximum torque result-ing in exf the timing ofthe two crankshafts will vary the tlming ofthe strokes of the separate such arotation of the planetary gearing as to change the timing of therespective l crank shafts in such a manner as to .reduce the amount offiuiddelivered by the ump. Even when the crank'shafts are tim 180 apart,however, it is impossible to obtain absolute zero delivery by. such aconstruction, due to the relative angularity (if the `variousconnecting-rods. That is to say,4that even with the cranks a. andv :vpositioned as shown-in Fig. 5 there would be some movement given to theplunger 12. The automeans of obtainiugzero delivery. If there isv nodemand 4whatever for pump `delivery the cross head 45 will continue to`move upwardly as long as vthere is an discharge from the pump and thisupwar movement .will linally cause the cross head to engage the switchv64 and break the solenoid circuit, permitting the spring 66 to expandplungers 72 in such'a way as to cause a corres onding variationin theump'delivery.

- lthough I have describedp a specific embodiment of-this invention itwill be apparent that various changes, additions, modifications andsubstitutions can-be made thereinfwithout departing from the spirit oftheV invention or the scope of theappended claims.

What Iclaim as new and desire' securef `by Letters'Patent is 1. Avariable' deliverypump having in combination parallel operating shaftsrotatably mounted in fixed relation and means for varying \the relativetiming of said shafts.

2. A-variable delivery pumphaving in' combination parallel crank shafts.mounted p jin fixed relation toeach other' and means matic switch 64,however, provides' a simple for changing the relativetiming ofsaidshafts for varyingythe `delivery of said' pump.

3. The combination in va pump .otwof parallel fixed crank' shafts andmeans for-` vrying Athe timing of said shafts during operation'of thepump so as to vary the delivery of lsaid pump without Changingjhe speedthereof. s f t ico 4. The combination in a variable delivery pump of twoparallel crank shafts mounted in fixed relation, gears connecting saidcrank shafts for simultaneous operation, means for drivingr said crankshafts and means for varying the relation of said gears so as to changethe timing of said crank shafts and vary the delivery of said pump.

5. The combination in a variable delivery pump of two parallel crankshafts mounted in fixed relation, a planetary gear train connecting saidshafts for simultaneous rotation, means for driving said shafts andmeans for so controlling said planetary gear train as to vary the timingof said crank shafts so as to vary the delivery of said pump.

6. The combination in a variable delivery pump of parallel crank shaftsmounted in fixed relation, a planetary gear train connecting said crankshafts for simultaneous rotation, means for driving said shafts andmeans subject to the discharge pressure of the pump for so controllingsaid gear train as to vary the timing of said crank shafts and vary thedelivery of said pump in accordance with changes in the dischargepressure thereof.

7. The combination in a variable deliver)1 pump of a pair of crankshafts adapted to be simultaneously rotated, plunger mechanism operatedby said crank shafts, means for simultaneously rotating said crankshafts including an annular gear connected to one of said shafts byintermediate planetary gears and means for shifting said planetary gearsrelatively to said annular gear so as to vary the relative timing ofsaid crank shaft.

8. The combination in a variable delivery pump of crank shafts mountedin fixed rela.- tion, a gearon each of said shafts for simultaneouslyrotating said shafts, an annular gear' supported upon one of said shaftsand meshing with the gear on the other'of said shafts, planetary gearingconnecting said annular gear with the other of said shafts and means forshifting said gearing so as to vary the relative timing of said shafts.

9. The combination in a variable delivery pump of separate crank shafts,plunger mechanism operatively associated therewith, means forcontrolling the timing' of said shafts so as to vary the delivery ofsaid pump, means for loading and unloading said pump and a movablemember responslve to the variations in the pressure of the pumpdischarge for automatically controlling the operation of said loadingand unloading means. A

10. The combination in a variable delivery pump of separate crankshafts, plunger mechanism operatively associated therewith, means forvarying the timing of said shafts so as to vary the pump delivery,mechanism including a solenoid for loading and unloading said pump, aswitch in the solenoid circuit and a movable member adapted to beshifted in accordance with variations in the pressure of the pumpdischarge for operatingfsaid switch so as to control said loading andunloading mechanism.

11. The combination in a variable delivery pump of separate crank shaftsmounted in fixed relation, gearing connecting said crank shafts forsimultaneous rotation, mechanism for loading and unloadin said pump,means for operating said mec ianism from said gearing, a solenoid forcontrolling the operation of said mechanism. a switch in the solenoidcircuit and a movable member adapted to be shifted in accordance withvariations in the pressure of the pump discharge for operating saidswitch so as to permit said pump to load and unload.

12. A variable delivery pump having iu combination parallel operatingshafts rotatably mounted in fixed relation and means responsive tovariations in the discharge pressure of the pump for varying therelative timing of said shafts.

13. The combination in a pump of two parallel crank shafts rotatablymounted in fixed relation and means responsive to variations in thedischarge pressure of the pump for varying the timing of'said shaftsduring operation of the pump so as to vary the delivery of said pumpwithout changing the speed thereof.

14. The combination in a variable delivery pum of two parallel crankshafts mounted in xed relation, gears connecting said shafts forsimultaneous operation, means for driving said crank shafts and meansresponsive to variations in the discharge pressure of the pump forvarying the relation of said gears to change the timing of said crankshafts and va the delivery of said pump.

15. The com ination in a variable delivery pump of separate crankshafts, gearing con necting said shafts for simultaneous rotation,mechanismfor loading and unloadin said pump and means for operating saimechanism from said gearing.

16. The combination in a variable delivery pump of separate crankshafts, plunger mechanism operatively associated therewith, means forcontrolling the timing of said shafts so as to vary the delivery of saidpump, means for loading and unloading said pump, and mechanism resonsive to the variations in the pressure of t e pump discharge vforsynchronizing the operation of said loading and unloading means with theoperation of said plunger mechanism.

In testimony whereof, I have hereunto subscribed my name this 11th dayof June, 1926.

JOSEPH E. HoLvEoK.

